Modular alarm signaling system

ABSTRACT

A system including a module for providing an audible or visual and electrical signal in response to a changed condition. The electrical signal is fed to a second module which provides a reversed polarity output on receipt of the signal. The reversed polarity output is coupled to a third remote module which provides a plurality of indications including an indication of normal conditions and alarm conditions. A fourth module provides power for the system and an auxiliary alarm indication.

United States Patent [72] Inventor Appl. No. Filed Patented Assignee MODULAR ALARM SIGNALING SYSTEM 8 Claims, 2 Drawing Figs.

US. Cl. 340/213 R [56] Reierencis Cited UNITED STATES PATENTS 3,267,450 8/1966 Thompson 340/213 3,345,628 10/1967 Jackson 340/213 X Primary Examiner-Stanley M. Urynowicz, Jr. Attorney-Robert A. Green ABSTRAQT: A system including a module for providing an audible or visual and electrical signal in response to a changed condition. The electrical signal is fed to a second module which provides a reversed polarity output on receipt of the signal. The reversed polarity output is coupled to a third remote module which provides a plurality of indications in- .....G08b 19/00 cluding an indication of normal conditions and alarm condi- Field of Search 340/213, tions. A fourth module provides power for the system and an 215 auxiliary alarm indication.

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.A GK Y 32 fig 390 i alo ll'illllll lJL/llll ALAlltl /l lillGl lALlll iG SYSTEM BACKGROUND OF THE lNVENTlON Alarm-signaling systems are about as old as man himself, and through the years, they have been improved as mans technology improved. The greater portion of alarm systems sold at the present time are electromechanical systems which include mechanical moving parts operated by relays. These systems lack reliability because the mechanical parts get dirty and wear out. In addition, such systems require considerable expensive battery power which requires constant replacement.

Slllvl MARY OF THE lNVENTlON The present invention provides a relatively simple low power, all-electronic system which is versatile in its alarm responsiveness and which can be readily modularized as separately operable units. The system can provide both local and remote alarm indications. Since the system is modular, it can be added to at any time.

DESCRlPTlON UlF Tl'lE DRAWTNG FlG. it is a schematic representation of two circuits which form a portion of the system ofthe invention; and

FIG. 2 is a schematic representation of two other circuit modules which combine with those of FIG. l in forming the system of the invention.

DESCRll-TlON OF THE PREFERRED Ell/llBODllMENT The system shown and described includes various semiconductor devices including diodes, transistors, and other switching devices. These devices are shown schematically in the form usually employed by the industry.

The system of the invention ltl comprises a first alarm condition sensing module Zll which includes a DC power source Sill connected between buses db and Stl. The module 20 has an alarm indicator including a three-electrode semiconductor gate or switching device fill known as an SCR connected in series with load resistor 70 between buses Ml and fill with an alarm bell or horn or the like represented by block llll con nected across resistor ill. The gate of SCR till is connected through a resistor ill. to bus 5ll and to negative potential. SCR fill is normally held off by the applied potentials. The anode of SCR dd is also coupled through diode ll and lead llllll to a second module Ellll, a polarity-reversing circuit, to be described.

A first alarm-sensing arrangement in module Zll includes a semiconductor switch lllli il, preferably a GE. 4987 unilateral switch, having its anode A connected through a resistor llllll to the bus ltl and to positive potential, and its gate G connected through a normally closed switch llltl and through a second DC power source l5ll to the bus dll. The cathode l( of switch 120 is connected to a lead llhil which is connected to resistor 82 and thus to negative reference potential or ground. Power sources Zlll and llStl normally hold switch ll2tl nonconducting, and switch l lll represents a mechanical or electronic sensor switch or any other sensing mechanism which, when opened, upsets the bias arrangement and permits switch H220 to conduct current from anode to cathode and to the gate of SCR bill which also then conducts, energizes alarm iltl, and provides an output current on lead urn from diode 90. Device lldll may be a fire alarm or the like, or it may be several alarm-sensing devices connected in parallel.

A second similar alarm-sensing arrangement in module includes a normally open switch ll'l'd which, like switch Mil, represents an alarm sensor connected in series with a resistor 180 between buses dll and 5d. Again, a plurality of similar alarm sensors might be connected in parallel. This sensing arrangement also includes a second similar unilateral switch 190 having its anode connected through a resistor Zlltl to bus lll and its gate connected to the lead 2W between resistor Zlltl and switch 117%. The cathode electrode of switch we is connected through a variable resistor 22d and capacitor 23b to bus Kill and through a second resistor Mil to the anode A of a unijunction transistor 250. The junction lltill of the variable resistor 22d and the capacitor 236' is connected to the trigger T of the unijunction transistor 250, and the cathode l( of the unijunction transistor is connected to the gate of the Still Ml. Resistor 22d and capacitor filIlll comprise adjustable timing circuit for controlling the charging time of capacitor 23M and the turn'on time of unijunction filfitl. This time-delay mechanism permits an authorized entrant to trip sensor ll'ltl and then reset it before alarm till is set oft".

Sensors M ll and ll'7lll are shown as normally closed and normally open, respectively, to indicate that module 2b can accommodate alarm sensors of different types in its two sensing circuit loops.

in the polarity'reversing module lllll, the lead lllll from module Hill is connected to the gate G of a unilateral switch Ztill, the anode A of which is connected through a resistor 27d to bus ill. Switch 26b is normally held nonconductive. The gate G is also connected through a resistor Ziltl to the bus ill. The cathode ii of the switch Ilhll is connected to the base of an NlN transistor E'iltl, the emitter of which is connected to the bus 5tl by lead 292, and the collector of which is connected to the base of a PNP transistor Elllll. The PNP transistor dlltl has its collector connected to the lead 292. and its emitter connected by lead Illlll to the base electrodes of two Phil transistors 320 and illlll. The emitter of the transistor 32s is connected to an output terminal Mill and through a load re' sistor 350 to the positive terminal of a DC power source Il'itl, the negative terminal of which is connected to the bus 50. The transistor 320 also has its collector electrode connected to the bus 50. The transistor llllll has its emitter electrode connected to the lead lldtl, and its collector electrode connected both to an output terminal Sltlil and through a load resistor 3W9 the bus 5tl.

Module illll operates as follows. With module Ell quiescent and no alarm condition present, no signal is conducted through diode Ml to module Hill, and this module is quiescent. in the quiescent state of module llllll, switch Zbll and all transistors are nonconducting and terminal carries posi tive potential and terminal 3tlfll carries negative potential. When an alarm condition in module ill provides current flow on lead llllll, switch ZQ'rll conducts and transistors 2m and 311W turn on, and this causes transistors 321! and 33b to turn on. Now, the emitter of transistor 32d assumes a negative potential, as does terminal ll ltl, and the collector of transistor 33% assumes a positive potential, as does terminal Mill. Thus, it can be seen that the normal polarity of terminals Ell'll and Elbt are reversed during an alarm-indicating condition of the system.

Lines dllll and Hill are input leads to module lltl and are coupled to terminals Mill and Iltlll at the output of module lllt Lines Aliltl and dill represent telephone lines or the like to a remote location, for example, a police station, firehouse, or the like, at which module 4120 may be remotely located.

Line dlllll is coupled through a diode d2 oriented as shown to line Alllll. Line lltl is coupled through an oppositely oriented diode Mil as shown to line use. lsine dt'l ll is also coupled through lead me and a diode l'l il oriented oppositely to diode 422 to line Mill, and line lllll is also connected through lead mil to a diode Still oriented oppositely to diode Mil to line iiilll. Lines drill and dllll are connected together by a lead 5%, and line 43b is coupled to the base electrodes of two NlPN transistors 530 and Will. Line Fillil is coupled to the base electrode of another NPN transistor 55b.

The module Mill includes a first trouble light Still in series with an SCR 570, a normal" light 5% in series with an SCR 59d, and an alarm" light or signal tillll of any suitable type in series with an SClR ollll. The three condition-indicating devices fidll, 580, and Chllll are connected in parallel, with the cathodes of the SCRs connected together by lead (with and with the free terminal of each device connected together to lead 630 which is connected to one side of an AC power source 640. The gate electrodes of the SCRs are also connected through resistors 650 to a common bus 660 which represents reference potential and is connected by lead 670 to the other side of power source 640.

The first-described portions of module 420 and the alarm or normal" are interconnected as follows. The collector of transistor 530 is connected by lead 700 through resistor 710 to the gate of SCR 570 to trouble" indicator 560 and through resistor 720 and lead 730 to bus 740. The emitters of transistors 530 are connected through resistors 750 to lead 450 which is connected to reference bus 660. The emitter of transistor 540 is connected by lead 760 and resistor 770 to the gate of SCR 590 to the normal" indicator 580, and the collector of transistor 540 is connected through resistor 780 to bus 730 to the power supply.

Line 400 is connected through lead 460, diode 422, lead 480, resistor 790, lead 800 and resistor 810 to the gate of SCR 610 of alarm indicator 600. The emitter of transistor 550 is connected to lead 800 to SCR 610, and its collector is connected through resistor 820 and lead 740 to the power supply.

A pulse-generating circuit in module 420 includes connections from lead 510 to the base of transistor 550 through a resistor 830, lead 834, and capacitor 840 to bus 660. Lead 510 is also connected by lead 850 to the anode of SCR 860 which has its cathode connected through a resistor 870 to bus 660 and through a capacitor 880 and lead 890 to a remote alarm to be described. The gate of SCR 860 is connected to lead 834 and through a resistor 900 to bus 660.

The power supply for the system includes the usual 1 10 volt, 60 cycle AC power source 900 coupled to a transformer having primary and secondary windings 910 and 920, respectively. The secondary winding of the transformer has one end 903 connected through a lead 940 to lead 630 which is con nected to one side of each of the signal devices 560, 580, and 600. This connection provides alternating current across these devices between bus 630 and bus 660. This end of the secondary winding of the transformer is also connected through a diode 950 and lead 960 to the lead 740 to provide half-wave rectified DC on lead 740 and thus to lead 730. The other end 980 of the secondary winding of the transformer is connected by lead 970 and lead 670 to the reference bus 660. A capacitor 990 is connected between leads 960 and 970. This capacitor acts as a filter and phase shifter.

An auxiliary alarm circuit is also provided including an SCR 1000 having its cathode connected to the lead or bus 970 and its anode connected through a load resistor 1010, a lead, and a switch 1020 to the lead 960. A suitable alarm 1030 is connected across the load resistor 1010. The gate of the SCR 1000 is connected through a resistor to the reference bus 970 and to lead 890 to capacitor 880.

Referring to circuit module 420, as mentioned, when the system is normal, that is, no alarm condition exists in module 20, line 400 is plus and line 410 is minus. With line 400 plus, positive voltage is coupled through diode 422 to turn on both NPN transistors 530 and 540. With transistor 530 turned on, its collector is at ground potential so that the signal voltage which is applied to bus 740 from the power supply is fed to ground and SCR 570 is not turned on and trouble light 560 is not turned on. With NPN transistor 530 on, a path is provided through the emitter-collector path of transistor 530 for the signal on bus 740, and this is applied to the gate of SCR 590 which opens SCR 590 and turns on the normal" light 580.

If potential is removed from lines 400 and 410 for any reason, either due to opening of a line or shorting of the lines, then the transistors 530 and 540 remain off and trouble light 560 is turned on by the signal voltage on lines 740 and 730 passing through resistors 720 and 710 to the gate of SCR 570 which is rendered conductive.

When the potentials on lines 400 and 410 are reversed indicating an alarm condition, diodes 422 and 440 are blocked, transistors 530 and 540 are off and signal voltage is coupled from the power supply through lines 740 and 730 through resistor 720 to the gate of SCR 570 which conducts and trouble" light 560 goes on. Also, diodes 470 and 500 open, and the positive potential on line 410 now operates through diode 500, to turn on transistor 550. The emitter-collector path of transistor 550 passes signal voltage on line 740 through lead 800 and resistor 810 to the gate of SCR 610, which thereby conducts and turns on the alarm 600.

In addition, plus voltage applied to diode 500 is applied to the anode of SCR 860, and current flow through resistor 830 charges capacitor 840 which, when charged, acts on the gate of SCR 860 to turn on SCR 860 and send a pulse through capacitor 880 to turn on remote SCR 1000 and thus activate remote alarm 1030 shown in the power supply circuit. This arrangement using capacitor 840 prevents spurious noise pulses from turning on SCR 860 since such pulses are fed to ground through resistor 900 and do not charge the capacitor. Switch 1020 can be used to deactivate or turn off alarm 1030, if this is desired, without affecting the other alarms in the system.

What is claimed is:

1. An alarm sensing and indicating system including first alarm signalling means,

a first electronic circuit module including first bistable switching means having two states of operation, in one of which it is unenergized and quiescent and, in the second of which, it senses a first alarm condition and generates a first electrical signal in response thereto, said first electrical signal operating said first alarm signalling means,

a second electronic circuit module including second bistable switching means having two states of operation, in one of which it is unenergized and quiescent and, in the second of which, it senses a second alarm condition and generates a second electrical signal in response thereto, said second electrical signal operating said first alarm signalling means, and

a third electronic circuit module coupled to said first and second electronic circuit modules and having input terminals coupled thereto and also having first and second output terminals coupled to second signalling means for indicating which of its two states each of said first and second electronic circuit modules is in,

said output terminals of said third electronic circuit module carrying one set of potentials and energizing one portion of said second signalling means when said first and second circuit modules are in an unenergized and quiescent state, said output terminals carrying a second set of potentials and energizing another portion of said second signalling means when one or both of said first and second electronic circuit modules is in an alarm-signalling state.

2. The system defined in claim 1 wherein one of said first or second circuit modules includes time delay means for delaying its operation of said first alarm signalling means.

3. The system defined in claim 1 and including a fourth circuit module coupled to said third module and including first signalling means indicating a normal state for said system when said output signal is not present and said third module is in said first state, and second signalling means indicating an alarm state when said output signal is present and said third module is in said second state.

4. The system defined in claim 3 wherein said fourth module includes first circuit means including an alarm condition indicator and a gate, and second circuit means including a normal condition indicator and a gate,

first power supply means coupled to and applying an AC signal across both said alarm condition indicator and gate, and said normal condition indicator and gate, each said gate preventing said AC signal from turning on either indicator, and

a second power supply means coupled through control means to said gates for applying an enabling signal thereto and for operating the same and their associated indicators under control of said control means.

5. The system defined in claim 1 and including a fourth circuit module coupled to said third circuit module wherein said first and second output terminals of said third circuit module are coupled through a first pair of oppositely oriented diodes to a pair of switching devices,

one of said switching devices being coupled through a first circuit path to a first indicator representing trouble and through a second circuit path to a second indicator representing normal,

said first and second output terminals also being connected through a second pair of oppositely connected diodes to third and fourth circuit paths, said third circuit path including a circuit connection including a switching device to a third indicator representing trouble" and said fourth circuit path including a fourth remote trouble" indica tor, and

a signal source providing signals for operating said first, second, and third indicators and coupled to said first, second, and third circuit paths, said paths being open or blocked to said signals depending on the conductive state of said first and second pairs of devices, and the state of said diodes being determined by the potentials on said first and second output terminals of said third circuit module.

6. The system defined in claim 5 wherein said fourth circuit path includes a pulse generating circuit which comprises a switch and a capacitor, said switch being rendered conductive to operate said fourth trouble" indicator when said capacitor is charged by current flowing in said fourth circuit path as the result of an alarm condition sensed by said system.

7. The system defined in claim 1 and including a fourth circuit module coupled to said third circuit module wherein said first and second output terminals of said third circuit module are coupled through a first pair of oppositely oriented diodes to first and second switching devices which are connected so that they turn ON and OFF together in response to the potentials on said first and second output terminals of said third module,

said first switching device being coupled through a first circuit path to a first trouble" indicator having a first gate and through a second circuit path to a second normal" indicator having a second gate,

said first and second output terminals also being connected through a second pair of oppositely connected diodes to third and fourth circuit paths, said third path including a circuit connection including a switching device to a third trouble indicator having a third gate, said fourth path being coupled to a fourth remote "trouble" indicator having a fourth gate, and

a signal source providing signals for operating said first, second, and third indicators and coupled to said first, second, and third circuit paths, said paths being open or blocked to said signals depending on the conductive state of said first and second pairs of devices, and the state of said diodes being determined by the potentials on said first and second output terminals of said third circuit module.

8. The system defined in claim 7 wherein said first and second switching devices comprise first and second semiconductor devices coupled together and adapted to be ON or OFF together in response to signals on said first and second output terminals of said third module,

when said devices are ON together, they are in condition to couple signals from said signal source to said second gate to operate said second normal indicator and at the same time they are connected to prevent said signals from energizing said first gate and said. first trouble" indicator, when said devices are OFF together, said third and fourth circuit paths are operative and operate their indicators. 

1. An alarm sensing and indicating system including first alarm signalling means, a first electronic circuit module including first bistable switching means having two states of operation, in one of which it is unenergized and quiescent and, in the second of which, it senses a first alarm condition and generates a first electrical signal in response thereto, said first electrical signal operating said first alarm signalling means, a second electronic circuit module including second bistable switching means having two states of operation, in one of which it is unenergized and quiescent and, in the second of which, it senses a second alarm condition and generates a second electrical signal in response thereto, said second electrical signal operating said first alarm signalling means, and a third electronic circuit module coupled to said first and second electronic circuit modules and having input terminals coupled thereto and also having first and second output terminals coupled to second signalling means for indicating which of its two states each of said first and second electronic circuit modules is in, said output terminals of said third electronic circuit module carrying one set of potentials and energizing one portion of said second signalling means when said first and second circuit modules are in an unenergized and quiescent state, said output terminals carrying a second set of potentials and energizing another portion of said second signalling means when one or both of said first and second electronic circuit modules is in an alarm-signalling state.
 2. The system defined in claim 1 wherein one of said first or second circuit modules includes time delay means for delaying its operation of said first alarm signalling means.
 3. The system defined in claim 1 and including a fourth circuit module coupled to said third module and including first signalling means indicating a normal state for said system when said output signal is not present and said third module is in said first state, and second signalling means indicating an alarm state when said output signal is present and said third module is in said second state.
 4. The system defined in claim 3 wherein said fourth module includes first circuit means including an alarm condition indicator and a gate, and second circuit means including a normal condition indicator and a gate, first power supply means coupled to and applying an AC signal across both said alarm condition indicator and gate, and said normal condition indicator and gate, each said gate preventing said AC signal from turning on either indicator, and a second power supply means coupled through control means to said gates for applying an enabling signal thereto and for operating the same and their associated indicators under control of said control means.
 5. The system defined in claim 1 and including a fourth circuit module coupled to said third circuit module wherein said first and second output terminals of said third circuit module are coupled through a first pair of oppositely oriented diodes to a pair of switching devices, one of said switching devices being coupled through a first circuit path to a first indicator representing ''''trouble'''' and through a second circuit path to a second indicator representing ''''normal,'''' said first and second output terminals also being connected through a second pair of oppositely connected diodes to third and fourth circuit paths, said third circuit path including a circuit connection including a switching device to a third indicator representing ''''trouble'''' and said fourth circuit path including a fourth remote ''''trouble'''' indicator, and a signal source providing signals for operating said first, second, and third indicators and coupled to said first, second, and third circuit paths, said paths being open or blocked to said signals depending on the conductive state of said first and second pairs of devices, and the state of said diodes being determined by the potentials on said first and second output terminals of said third circuit module.
 6. The system defined in claim 5 wherein said fourth circuit path includes a pulse generating circuit which comprises a switch and a capacitor, said switch being rendered conductive to operate said fourth ''''trouble'''' indicator when said capacitor is charged by current flowing in said fourth circuit path as the result of an alarm condition sensed by said system.
 7. The system defined in claim 1 and including a fourth circuit module coupled to said third circuit module wherein said first and second output terminals of said third circuit module are coupled through a first pair of oppositely oriented diodes to first and second switching devices which are connected so that they turn ON and OFF together in response to the potentials on said first and second output terminals of said third module, said first switching device being coupled through a first circuit path to a first ''''trouble'''' indicator having a first gate and through a second circuit path to a second ''''normal'''' indicator having a second gate, said first and second output terminals also being connected through a second pair of oppositely connected diodes to third and fourth circuit paths, said third path including a circuit connection including a switching device to a third ''''trouble'''' indicator having a third gate, said fourth path being coupled to a fourth remote ''''trouble'''' indicator having a fourth gate, and a signal source providing signals for operating said first, second, and third indicators and coupled to sAid first, second, and third circuit paths, said paths being open or blocked to said signals depending on the conductive state of said first and second pairs of devices, and the state of said diodes being determined by the potentials on said first and second output terminals of said third circuit module.
 8. The system defined in claim 7 wherein said first and second switching devices comprise first and second semiconductor devices coupled together and adapted to be ON or OFF together in response to signals on said first and second output terminals of said third module, when said devices are ON together, they are in condition to couple signals from said signal source to said second gate to operate said second ''''normal'''' indicator and at the same time they are connected to prevent said signals from energizing said first gate and said first ''''trouble'''' indicator, when said devices are OFF together, said third and fourth circuit paths are operative and operate their indicators. 